#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>

int main()
{
    printf("process ids runing, only me!,pid:%d\n", getpid());
    sleep(3);
    pid_t id = fork();
    if(id == -1) return 1; // 创建失败
    else if(id == 0)
    {
        // child
        while(1)
        {
            printf("id: %d, I am child process, pid: %d, ppid: %d\n", id, getpid(), getppid());   
            sleep(1);
        }
    }
    else
    {
        // parent
        while(1)
        {
            printf("id: %d, I am parent process, pid: %d, ppid: %d\n", id, getpid(), getppid());   
           sleep(2);
        }
    }
    return 0;
}
